<template>
  <div class="box" ref="box">
    <div class="left">
      <!--左侧div内容-->
    </div>
    <div class="resize" title="收缩侧边栏">
      
    </div>
    <div class="mid">
      <!--右侧div内容-->
    </div>
  </div>
</template>

<script>
export default {
  methods: {
    dragControllerDiv() {
      var resize = document.getElementsByClassName('resize');
      var left = document.getElementsByClassName('left');
      var mid = document.getElementsByClassName('mid');
      var box = document.getElementsByClassName('box');
      for (let i = 0; i < resize.length; i++) {
        // 鼠标按下事件
        resize[i].onmousedown = function (e) {
          //颜色改变提醒
          resize[i].style.background = '#818181';
          var startY = e.clientY;
          resize[i].top = resize[i].offsetTop;
          // 鼠标拖动事件
          document.onmousemove = function (e) {
            var endY = e.clientY;
            var moveLen = resize[i].top + (endY - startY); // （endY-startY）=移动的距离。resize[i].left+移动的距离=左边区域最后的宽度
            var maxT = box[i].clientHeight - resize[i].offsetHeight; // 容器宽度 - 左边区域的宽度 = 右边区域的宽度
            if (moveLen < 32) moveLen = 32; // 左边区域的最小宽度为32px
            if (moveLen > maxT - 150) moveLen = maxT - 150; //右边区域最小宽度为150px
            resize[i].style.top = moveLen; // 设置左侧区域的宽度
            for (let j = 0; j < left.length; j++) {
              left[j].style.height = moveLen + 'px';
              mid[j].style.height = (box[i].clientHeight - moveLen - 10) + 'px';
            }
          };
          // 鼠标松开事件
          document.onmouseup = function (evt) {
            //颜色恢复
            resize[i].style.background = '#d6d6d6';
            document.onmousemove = null;
            document.onmouseup = null;
            resize[i].releaseCapture && resize[i].releaseCapture(); //当你不在需要继续获得鼠标消息就要应该调用ReleaseCapture()释放掉
          };
          resize[i].setCapture && resize[i].setCapture(); //该函数在属于当前线程的指定窗口里设置鼠标捕获
          return false;
        };
      }
    },
  },
  mounted() {
    this.dragControllerDiv();
  }
}
</script>

<style >
/* 拖拽相关样式 */
/*包围div样式*/
.box {
  width: 100%;
  height: 100%;
  margin: 1% 0px;
  overflow: hidden;
  box-shadow: -1px 9px 10px 3px rgba(0, 0, 0, 0.11);
  display: flex;
  flex-direction: column;
}

/*左侧div样式*/
.left {
  width: 100%; /*左侧初始化宽度*/
  height: 50%;
  background: #0a80ff;
}

/*拖拽区div样式*/
.resize {
  cursor: row-resize;
  position: relative;
  background-color: #d6d6d6;
  border-radius: 5px;
  width: 100%;
  height: 10px;
  background-size: cover;
  background-position: center;
  font-size: 32px;
  color: white;
}

/*拖拽区鼠标悬停样式*/
.resize:hover {
  color: #444444;
}

/*右侧div'样式*/
.mid {
  width: 68%; /*右侧初始化宽度*/
  height: 100%;
  box-shadow: -1px 4px 5px 3px rgba(0, 0, 0, 0.11);
  background: #d70505;
}
</style>